1. Field of the Invention
This invention relates to an ink-jet head, more particularly to an ink-jet head for generation of small ink droplets for recording, used for the so called ink-jet recording system, and to a method for production thereof.
2. Description of the Prior Art
An ink-jet head to be applied for the ink-jet recording system is generally provided with minute ink discharging outlets (orifices) having apertures of about some 10.mu. to 100.mu., ink flow paths and portions for generating ink discharging pressure provided at a part of said ink flow paths.
In the prior art, as the method for preparing such an ink-jet head, there has been known, for example, a method in which minute grooves are formed by way of cutting or etching on a plate of a glass or a metal, and then the plate having such grooves is bonded to another appropriate plate for formation of ink flow paths. There were formerly made proposals relating to ink-jet heads constituted by utilization of photosensitive resin compositions, as disclosed in U.S. patent application Ser. No. 238,422, German Laid-open Patent Application No. 31 08 206, and British Laid-open patent application No. 20 72 099.
The ink-jet head proposed above has the various features set forth below:
(1) Since the main process steps in the fabrication of the ink-jet head rely on a so called photographic technique, highly precise and delicate portions in the head can be formed very simply by the use of desired patterns. In addition, a multitude of heads having the identical constructions may be worked simultaneously.
(2) The relatively few manufacturing steps result in a high productivity.
(3) Since registration among the principal structural portions constituting the head can be done easily and accurately, the ink-jet head having high dimensional precision can be obtained readily.
(4) Multi-array ink-jet heads of high density can be manufactured by a simple method.
(5) Since the depth of the groove constituting the ink flow path can be adjusted with extreme easiness, the ink path having a desired dimension can be formed depending on the layer thickness of the photosensitive (resin) composition.
(6) The ink-jet heads can be manufactured continuously and in an industrialized mass-production.
(7) Since there is no necessity for using etchant (strong acids such as hydrofluric acid and the like), the process is safe and hygienic.
On the other hand, a part of the ink-jet head may frequently be broken in the course of driving thereof, thus involving the drawback of being insufficient in so called usage life (or durability) in its practical application.